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Topic Review (Newest First)

04-08-2014 12:33 PM

BuzzLOL

Quote:

Originally Posted by ericnova72

That linked gasket still won't work though, it will overhang the piston ring starter chamfer at the top of the bore and become a hot spot...got to be like I said, 4.180" or bigger bore gasket....if you didn't advise the machinist to put the most minimal chamfer back on after boring the cylinders (I'm guessing no to this as you didn't previously know the fact).

. Didn't think anyone champfered the tops of the cylinder bores anymore... I don't... just use a good ring compressor to install the pistons... any champfers on the bore or piston tops are places where mixture can hide and not burn... costing power and producing a dirty running, polluting engine... champfers also lower compression ratio...

04-08-2014 01:19 AM

lumberjack_43

The 400 in my truck has never had a problem either hottest it ever seen was 210 but that was in a thick nasty hole and it took me 3 and a half mins of WOT to go 200 feet lol

04-07-2014 03:08 PM

ericnova72

I have no problem cooling the 400's I've done either, stock water jackets or half filled with block filler. Good radiator, good stock waterpump from a Air Conditioned car application, and the correct pulley ratio and it is no problem.

The Hot running 400 myth lives on, swap a used 400 in place of a 350 keeping the 350's single row radiator that's 10 years old and partially plugged up and of course it won't stay cool. .......But it's the 400's fault, right LOL

04-07-2014 02:52 PM

allend43

[QUOTE=1Gary;2251178]The 400's can use all the help it can get for cooling.

I had a half filled with Rockblock 406 with the deck plugged. I had cooling problems with it too. I used a Griffen aluminum radiator with a dual fan setup. It always ran 140 degrees, so I put the fans on a thermal switch instead of just on with the key, but it still ran only 160 at best. Finally took out 160* thermostat and put in a 180* and finally it would run at 180* If you fill block though, you need to watch oil temps when extended cruising on the street.

Has anyone blocked the steam holes? if it only starts goes to line races 200 feet then back to the trailer and shut off would i hurt anything by plugging them? besides making me heat faster

I keep forgetting about those darn steam holes on the 400s

The 400's can use all the help it can get for cooling.

Quote:

Originally Posted by ericnova72

In your case they can be blocked, they are often plugged for added strength in applications not being run at low rpm (3000 and above most all the time).They plug them using allen set screws...but don't do this on a finish machined block, only plug them before it gets bored and honed as it will distort things when they are installed.

Just allow the gasket to block them off in your case.

That linked gasket still won't work though, it will overhang the piston ring starter chamfer at the top of the bore and become a hot spot...got to be like I said, 4.180" or bigger bore gasket....if you didn't advise the machinist to put the most minimal chamfer back on after boring the cylinders (I'm guessing no to this as you didn't previously know the fact).

No bore or hone with using torque plates.No bore without sonic checking.Filling haft way up the expansion plugs with block filler helps stabilize the bores.Thin decks and thin wall bores.

04-05-2014 08:01 PM

ericnova72

Quote:

Originally Posted by vinniekq2

re look at the cam I already posted then. Maybe go slightly bigger? and contrary to Eric but not arguing,consider 102º ICL.
note: when that cam hits its peak power,thats all you get,the power rolls off fast

I wouldn't have a problem with that...106° lobe separation, 102° intake lobe centerline.

04-05-2014 07:55 PM

vinniekq2

re look at the cam I already posted then. Maybe go slightly bigger? and contrary to Eric but not arguing,consider 102º ICL.
note: when that cam hits its peak power,thats all you get,the power rolls off fast

04-05-2014 12:30 PM

ericnova72

If you haven't ordered the heads yet, go with a smaller chamber than 75 cc if you are planning race gas or E85 or alcohol.......64cc heads and flat top pistons will get you about 10.9-1 to 11.5-1 compression depending on how much the block has been decked....12.1-1 if you order 60 cc chambers from AFR.

In your case they can be blocked, they are often plugged for added strength in applications not being run at low rpm (3000 and above most all the time).They plug them using allen set screws...but don't do this on a finish machined block, only plug them before it gets bored and honed as it will distort things when they are installed.

Just allow the gasket to block them off in your case.

That linked gasket still won't work though, it will overhang the piston ring starter chamfer at the top of the bore and become a hot spot...got to be like I said, 4.180" or bigger bore gasket....if you didn't advise the machinist to put the most minimal chamfer back on after boring the cylinders (I'm guessing no to this as you didn't previously know the fact).

Won't work with a 400, no steam holes and is too close to the 4.155" bore size(of an .030" overbore) because you have to allow for the little chamfer at the top of the cylinder bores. 4.180" bore gasket is about as small as you can go on a .030" overbore 400.

Well just from reading online it seemed the .030ish were what was being used. What should i use then?

You should try to use a gasket that gets you near the ideal .038-.045" piston-to-head clearance (quench)......but what I am saying is there are not a lot of gasket thickness choices for the bigger 4.125" 400 engine as compared to the 4.000" SBC bore engines. You can't just pull the thickness # out of thin air....You may not be able to get a .027 or .030" thick gasket without having to custom order it. This is the reason decking the block is mentioned so much in build threads here , there are only a few available off the shelf gasket thicknesses so you have to deck to get ideal clearances. .038, .041, .051, .055" I know are available ....you may have to search to see if something thinner is now available for the 400, I haven't looked in a while. Cometic may now have something thinner in an MLS gasket for that bigger bore.

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